This invention relates to the electro-magnetic testing of a wire rope.
The applicant's European patent No. 87810158.3 describes a procedure for simultaneously testing a wire rope to determine variations in three characteristics, namely the cross sectional area of the rope, the wire contact pattern within the rope, and the existence of broken wires. Use is made of a magnetic test head which establishes two magnetic fields which magnetize adjacent sections of the rope in opposing directions. The rope is caused to move along a path through the head and the existence of the three characteristics referred to is detected by means of suitable sensors located at positions defined relatively to the head.
When the aforementioned head is operated the various sensors are positioned close to the rope at optimum locations. The rope moves relatively slowly to the test head under controlled conditions during the testing process.
If the test head is left in situ and the wire rope is used for normal operation, and travels at normal operating speeds, then the test head, or the rope, may be damaged by the lateral movement of the wire rope which takes place when the rope speed is increased. If use is made of guides such as rollers or the like to stabilize the rope when it passes through the test head, unnecessary wear may be caused to the rope.